Icephobic coating on the condenser cold side

ABSTRACT

An icephobic coating is disposed on at least a cold side of a condenser in an environmental control system (ECS) of an aircraft. By applying the icephobic coatings to the condenser, the adhesive strength of the ice can be significantly reduced. As a result, it is difficult for ice to stick on the condenser. The vibration in the system and the force of the air flow can then knock the ice particles off of the condenser, resulting in reduced ice buildup.

BACKGROUND OF THE INVENTION

The present invention relates to apparatus and methods for preventingice build-up and, more particularly, apparatus and methods forpreventing ice build-up on the cold side of environmental control system(ECS) condensers.

The air temperature at the turbine exit in an ECS system can besub-freezing. This causes moisture in the air to come out of the turbineas ice. This ice then sticks and starts building up on the cold side ofthe ECS condenser, which adversely affects the performance of both thecondenser and the ECS.

Conventional processes to prevent ice from building up require featuresin the system such as a bypass gap, hot bars and the turbine bypassvalve. These features decrease the overall performance as well as thereliability of the system.

As can be seen, there is a need for a method and apparatus that preventsice from building up on a device because of sub-freezing air exiting aturbine in an ECS system.

SUMMARY OF THE INVENTION

In one aspect of the present invention, an icephobic composition for astructure in a sub-freezing air flow comprises of a silicon resin bindercontaining fumed silica and a chemical crosslinker.

In another aspect of the present invention, an environmental controlsystem comprises a turbine supplying sub-freezing air to a condenser; acondenser adapted to receive the sub-freezing air; and an icephobiccoating disposed on at least a cold side of the condenser.

In a further aspect of the present invention, a method for preventingice buildup on a condenser comprises coating at least a cold side of thecondenser with an icephobic coating.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdrawings, description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of an environmental control systemfor an aircraft; and

FIG. 2 is a perspective view of offset fins that go into a condenseradapted to be coated with the icephobic coating of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplatedmodes of carrying out exemplary embodiments of the invention. Thedescription is not to be taken in a limiting sense, but is made merelyfor the purpose of illustrating the general principles of the invention,since the scope of the invention is best defined by the appended claims.

Various inventive features are described below that can each be usedindependently of one another or in combination with other features.

Broadly, embodiments of the present invention provide an icephobiccoating that may be disposed on at least a cold side of a condenser inan environmental control system (ECS) of an aircraft. By applying theicephobic coatings to the condenser, the adhesive strength of the icecan be significantly reduced. As a result, it is difficult for ice tostick on the condenser. The vibration in the system and the force of theair flow can then knock the ice particles off of the condenser,resulting in reduced ice buildup.

Referring now to FIG. 1, air may be received by an ECS 20 from both theaircraft exterior as fresh air, and from the aircraft fuselage or otherinterior space as recirculation air. Fresh air can be supplied fromcabin compressors 10 a, 10 b powered by motors 11 a, 11 b. Thecompressed air may pass through a primary heat exchanger 32 that may bedisposed in a ram air heat exchanger circuit 56. The ram air heatexchanger circuit 56 may have ambient ram air passing therethrough,which cools compressed air in the primary heat exchanger 32, a secondaryheat exchanger 34, and an air recirculation heat exchanger 36 located inthe circuit 56. The ambient ram air may be drawn into the heat exchangercircuit 56 through a ram scoop during aircraft flight. When the aircraftis stationary, the ram air heat circuit 56 may be driven by an electricfan 54 disposed downstream of the heat exchangers 32, 34, 36 so the heatfrom the fan 54 is directed overboard rather than into the heatexchangers 32, 34, 36. The ambient ram air in the circuit 56 is coolerthan the air passing through the heat exchangers 32, 34, 36, andtherefore serves as a heat sink.

After the compressed air passes through the primary heat exchanger 32,the air is supplied to a bootstrap air cycle machine, referringspecifically to a compressor 40 and a turbine 42 that either share thesame rotating axis or are otherwise powered and rotated together. Thecompressor 40 can further pressurize and heats the air. The compressedair can then be supplied to the secondary heat exchanger 34, causing thecompressed air to cool. During normal operation, an altitude valve 60may be closed, causing the air to pass through a re-heater 44 and acondenser 46, and then through a water separator 48, which substantiallydries the air. From the water separator 48, the air may again be heatedin the re-heater 44, and then the hot and dry air may be supplied to theturbine 42. The turbine 42 may provide cooled air as a product of airexpansion, and may forward the cooled air to the condenser 46, whichsupplies the air to the cabins in the aircraft fuselage 30.

The cooled air provided by the turbine 42 is typically sub-freezing.This can cause moisture in the air to come out of the turbine as ice.This ice may then stick and start to build up on the cold side of thecondenser 46. When the condenser 46 is coated with an icephobic coating50 (not shown in FIG. 1), the icephobic coating 50 may facilitateremoval of ice by reducing adhesion to the underlying surface, allowingsystem vibrations or airflow to discard ice from the condenser.

Typical offset fins used in a condenser 46 is shown in FIG. 2. It shouldbe noted that the icephobic coating 50 of the present invention may beapplied to various condenser designs, including the offset fin surface46, as shown, but also to plain fin and wavy fin condensers.

To create the coated condenser of the present invention, the icephobiccoating 50 may be applied to the condenser surface 46 through any numberof processes. For example, the icephobic coating 50 may be sprayed ontothe condenser fins 46 or the condenser 46 may be dipped into theicephobic coating 50, for example.

In some embodiments of the present invention, the icephobic coating 50may be applied to only a cold side of the condenser 46. For example, theicephobic coating 50 may be applied to about 50 percent of the length ofthe condenser 46. In some embodiments, the icephobic coating 50 may beapplied to the entire surface of the condenser 46.

The icephobic coating 50 may be selected from a number of icephobiccoatings. For example, the icephobic coating 50 may be applied as asilicone resin binder containing fumed silica particles and a chemicalcross linker. The coating can be either sprayed onto the condenser finsor the entire condenser can be dipped into the coating.

It should be understood, of course, that the foregoing relates toexemplary embodiments of the invention and that modifications may bemade without departing from the spirit and scope of the invention as setforth in the following claims.

We claim:
 1. An environmental control system comprising: a turbinesupplying sub-freezing air to a condenser; a condenser adapted toreceive the sub-freezing air; and an icephobic coating disposed on atleast a cold side of the condenser.
 2. The environmental control systemof claim 1, wherein the icephobic coating is disposed on the entirecondenser.
 3. The environmental control system of claim 1, wherein theicephobic coating includes a silicone resin binder containing fumedsilica particles and a chemical cross linker.
 4. A method for preventingice buildup on a condenser, the method comprising: coating at least acold side of the condenser with an icephobic coating.
 5. The method ofclaim 4, wherein the icephobic coating is disposed on the entirecondenser.
 6. The method of claim 4, wherein the icephobic coating isdisposed on a cold side of the condenser.
 7. The method of claim 4,wherein the icephobic coating includes a silicone resin bindercontaining fumed silica particles and a chemical cross linker.
 8. Amethod for preventing ice buildup on a condenser, the method comprising:coating at least a cold side of the condenser with an icephobic coating,wherein the icephobic coating includes a silicone resin bindercontaining fumed silica particles and a chemical cross linker.